A multi-scale prediction method for low-temperature sealing performance of hydrogen fuel cells

Abstract

The present application relates to a kind of hydrogen fuel cell low temperature sealing performance multiscale prediction method, method includes: S1, the initial actual compression of hydrogen fuel cell rubber seal under low temperature load is calculated, after optimization to actual compression, the modified compression rate is obtained, the actual low temperature compression rate of hydrogen fuel cell seal is obtained;S2, based on the influence of numerical method analysis rubber seal surface microtopography on the contact characteristics of hydrogen fuel cell sealing interface under low temperature, obtain the promotion term and inhibition term of interface sealing performance by the change of seal surface microtopography under low temperature;S3, based on promotion term and inhibition term and actual low temperature compression rate, obtain the prediction result of hydrogen fuel cell low temperature sealing performance.Compared with prior art, the present application has the advantages of fully considering the change of characteristic parameter of rubber seal at different scales under low temperature, and improving the prediction accuracy of hydrogen fuel cell low temperature leakage rate.

Description

TECHNICAL FIELD

[0001] The application relates to the field of hydrogen fuel cell sealing, and in particular to a hydrogen fuel cell low-temperature sealing performance multi-scale prediction method. BACKGROUND

[0002] As a new type of power generation system, hydrogen fuel cells have the ability to directly convert chemical energy into electrical energy and are considered to be cleaner and more efficient future energy systems. Hydrogen fuel cells face harsh working conditions such as low-temperature operation and cold start after standing during use. The sealing material becomes hard, the elastic modulus increases, the number and width of the gas leakage channels are different from those at room temperature, and the real leakage rate of the sealing material is difficult to predict.

[0003] The hydrogen fuel cell stack is a long string connection system, and the whole stack life and reliability under low-temperature environment depend on the worst temperature stability of the components. At present, the reaction gas leakage caused by the failure of rubber sealing elements is one of the main factors. In a 100kw stack, the number of sealing surfaces is more than 800 and the sealing length is more than 1500 meters. Failure of any part of any sealing element will cause gas leakage of the whole stack.

[0004] The sealing performance of the hydrogen fuel cell rubber sealing element is seriously affected by the influence of factors such as changes in material properties, geometric size shrinkage and weakening of resilience characteristics in low-temperature environment. Rubber sealing elements even fail in ultra-low-temperature environment, and reaction gas in hydrogen fuel cells leaks under the action of pressure difference between the inside and outside space. The study of low-temperature sealing performance of hydrogen fuel cells is an important basis for effectively improving the low-temperature life and cold start ability of the stack.

[0005] On a macro scale, the rubber sealing element in the hydrogen fuel cell is affected by low temperature and exhibits temperature-induced shrinkage behavior. Temperature-induced shrinkage not only appears in the size change of the sealing element, but also includes the phenomenon of elastic weakening of the rubber sealing element under long-term low temperature, which together affects the low-temperature sealing performance of the hydrogen fuel cell. Temperature-induced shrinkage widely exists in nature and has a serious negative impact on engineering practices such as civil construction, cable layout and sealing design.

[0006] But the essence of sealing failure is the overflow behavior of the sealing medium from the interface gap under the action of the pressure difference on both sides of the sealing interface, and the macroscopic research cannot calculate the interface leakage rate, and it does not have the ability to reveal the essence of the interface leakage. The research on the contact characteristics of the rough sealing interface of the hydrogen fuel cell at low temperature on the micro scale is an important part of building a low temperature sealing performance model and revealing the low temperature sealing failure mechanism. The surface micro topography of the hydrogen fuel cell seal changes under the influence of temperature load, and the low temperature load will make the originally rough surface protrusions become smoother, which will help to reduce the sealing interface gap and gas leakage; on the other hand, the change of the micro rough topography will increase the interface leakage channel height, which will reduce the difficulty of gas flow overflow and increase the gas interface leakage rate.

[0007] It can be seen from the above that the influence of temperature on the performance of the hydrogen fuel cell seal cannot be ignored, and the current analysis of the low temperature sealing performance of the hydrogen fuel cell and the design of the low temperature sealing structure only consider the size change of the rubber seal under the temperature load, without considering the influence of the weakening of the rubber material elasticity on the macroscopic, and without analyzing the low temperature sealing capacity of the seal according to the change of the micro topography, resulting in a large deviation when predicting the low temperature leakage rate of the hydrogen fuel cell by using the traditional method, or it is difficult to meet the real working requirements when designing the low temperature sealing structure. SUMMARY

[0008] The purpose of the present application is to fully consider the change of the characteristic parameters of the rubber seal at different scales at low temperature and to improve the prediction accuracy of the low temperature leakage rate of the hydrogen fuel cell, and a multi-scale prediction method for the low temperature sealing performance of the hydrogen fuel cell is provided.

[0009] The purpose of the present application can be realized by the following technical scheme:

[0010] A multi-scale prediction method for the low temperature sealing performance of the hydrogen fuel cell, the method comprising:

[0011] S1, calculating the initial actual compression amount of the hydrogen fuel cell rubber seal under low temperature load, and obtaining the corrected compression rate ΔH after optimizing the actual compression amount t , obtaining the actual low temperature compression rate η of the hydrogen fuel cell seal t ;

[0012] S2, analyzing the influence of the surface micro topography of the rubber seal on the contact characteristics of the hydrogen fuel cell sealing interface at low temperature based on the numerical method, obtaining the promotion item and the inhibition item of the interface sealing performance caused by the change of the surface micro topography of the seal at low temperature;

[0013] S3, obtaining the prediction result of the low temperature sealing performance of the hydrogen fuel cell based on the promotion item and the inhibition item and the actual low temperature compression rate.

[0014] Further, the actual compression amount is:

[0015] ΔH t初 = H t -B = H x [1-αx(25-t)]-B

[0016] Wherein, H t is the thickness of the hydrogen fuel cell rubber seal under the influence of low-temperature load; t is the specific temperature of the low-temperature environment; α is the temperature shrinkage coefficient of the seal rubber material, H is the thickness of the rubber seal in a free state; B is the depth of the sealing groove.

[0017] Further, the correction compression rate ΔH t is:

[0018] ΔH t = K C x(H t -B)

[0019] Wherein, K C is the compression cold resistance coefficient of the rubber seal material under low-temperature environment.

[0020] Further, the actual low-temperature compression rate η t is:

[0021]

[0022] Further, the hydrogen fuel cell low-temperature sealing performance prediction result is:

[0023] σ mul = σ tra + σ(D t )-σ(h t )

[0024] Wherein, σ tra represents the actual low-temperature compression rate η t , σ(D t ) represents the improvement item of the interface sealing performance of the seal surface micro-morphology change under low-temperature, and σ(h t ) represents the inhibition item of the interface sealing performance of the seal surface micro-morphology change under low-temperature.

[0025] Further, the improvement item of the interface sealing performance of the seal surface micro-morphology change under low-temperature is:

[0026] σ(D t ) = η t ·E t ·f(D t )-η·E·f(D)

[0027] Wherein, D and D trespectively refer to the surface micro-morphology characteristic parameters of the rubber seal under normal temperature and low temperature environment, f(D) and f(D t ) are respectively the surface micro-morphology change rule equations of the seal, and η represents the compression deformation degree caused by the extrusion section, and E and E t respectively represent the mechanical characteristic parameters of the rubber material of the seal under normal temperature and low temperature conditions.

[0028] Further, the surface micro-morphology change rule equation of the seal is fitted by an experimental method.

[0029] Further, the surface micro-morphology change rule equation of the seal is fitted by a numerical method.

[0030] Further, the inhibition term of the surface micro-morphology change of the seal under low temperature to the interface sealing performance is:

[0031]

[0032] Wherein h and h t respectively refer to the interface leakage channel height of the multi-layer ultra-thin sealing structure of the hydrogen fuel cell under the influence of the surface micro-morphology characteristics of the seal under normal temperature and low temperature environment.

[0033] Further, the compression rate represents the compression deformation degree caused by the extrusion section after the seal is installed in the sealing groove.

[0034] Compared with the prior art, the present application has the following beneficial effects:

[0035] The present application fully considers the change of the characteristic parameters of the rubber seal at different scales under low temperature, and is more accurate for predicting the sealing performance of the hydrogen fuel cell under low temperature, and the expression of the temperature-induced shrinkage behavior of the rubber seal in the low temperature environment based on the analytical method is very clear and fast. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is the flow chart of the present application;

[0037] Figure 2 is the schematic diagram of the multi-scale change of the characteristic parameters of the rubber seal of the hydrogen fuel cell under low temperature in the embodiment of the present application;

[0038] Figure 3 is the influence rule of the temperature-induced shrinkage on the actual compression rate of the rubber seal of the hydrogen fuel cell in the macroscopic scale in the embodiment of the present application;

[0039] Figure 4 is the multi-scale contact behavior of the rough sealing interface in the experimental group and the control group in the embodiment of the present application, wherein Figure 4 (a) of the experimental group is the result of considering the influence of the rough morphology on the contact behavior of the sealing interface,Figure 4 (b) is a control group result not considering the effect of the surface micro-topography of the rubber seal on the result of the interface contact behavior;

[0040] Figure 5 (b) is a control group result not considering the effect of the surface micro-topography of the rubber seal on the result of the interface contact behavior; DETAILED DESCRIPTION

[0041] The present application will be described in detail below with reference to the accompanying drawings and specific embodiments. The embodiments are implemented on the basis of the technical solutions of the present application, and detailed implementation methods and specific operation processes are given, but the protection scope of the present application is not limited to the following embodiments.

[0042] The present application provides a multi-scale prediction method for low-temperature sealing performance of a hydrogen fuel cell, and a flow chart is shown in Figure 1 The method comprises the following steps:

[0043] S1, calculating the initial actual compression amount of the rubber seal of the hydrogen fuel cell under low-temperature load, and obtaining the corrected compression rate ΔH after optimizing the actual compression amount t , and obtaining the actual low-temperature compression rate η of the hydrogen fuel cell seal t ;

[0044] S2, based on the numerical method, analyzing the influence of the surface micro-topography of the rubber seal on the contact characteristics of the sealing interface of the hydrogen fuel cell under low temperature, and obtaining the promotion item and the inhibition item of the surface micro-topography change of the seal under low temperature on the interface sealing performance;

[0045] S3, based on the promotion item and the inhibition item and the actual low-temperature compression rate, obtaining the prediction result of the low-temperature sealing performance of the hydrogen fuel cell.

[0046] The schematic diagram of the multi-scale change of the characteristic parameters of the rubber seal of the hydrogen fuel cell under low temperature in the embodiments of the present application is shown in Figure 2 .

[0047] First, the actual low-temperature compression rate of the rubber seal on the macro scale is mathematically modeled by using an analytical method; then the influence of the surface micro-topography of the rubber seal on the low-temperature contact state of the sealing interface of the hydrogen fuel cell is analyzed by using a numerical method; finally, a multi-scale prediction method for the low-temperature sealing performance of the hydrogen fuel cell is proposed by combining the macro analytical modeling and the micro numerical analysis. Compared with the prior art, the multi-scale method involved in the present application is more accurate in predicting the low-temperature sealing performance of the hydrogen fuel cell, and can better guide the low-temperature sealing structure design of the hydrogen fuel cell.

[0048] Hydrogen fuel cell monomer has the output characteristic of "large current, small voltage", in order to make it meet the actual engineering use, 300-500 monomer cells are generally connected in series to form a stack. For hydrogen fuel cell stack, failure or damage of any component in low temperature environment will greatly reduce the electrochemical efficiency of the whole stack or even completely stop running. Compared with other components, the rubber seal is simultaneously present in the anode and cathode of the hydrogen fuel cell, and the number of rubber seals in a stack is about twice that of other components, and the rubber seal is prone to unstable contact state, increased internal stress and even cracking and damage in low temperature environment, and the instability of the rubber seal in low temperature environment has become one of the important factors restricting the low temperature sealing performance and low temperature life of the hydrogen fuel cell. The present application simultaneously considers the influence of the change of the macroscopic and microscopic parameters of the seal under low temperature load on the sealing contact state, analyzes the multi-scale contact characteristics of the low temperature sealing interface of the hydrogen fuel cell, and finally proposes a multi-scale prediction method for the low temperature sealing performance of the hydrogen fuel cell, which provides a basis for the low temperature sealing life prediction and low temperature sealing structure design of the hydrogen fuel cell.

[0049] Compared with the prior art, the present application has the following advantages:

[0050] 1. The change of the characteristic parameters of the rubber seal at different scales under low temperature is fully considered, and the prediction of the sealing performance of the hydrogen fuel cell under low temperature is more accurate;

[0051] 2. The expression of the temperature-induced shrinkage behavior of the rubber seal in the low temperature environment on the macroscopic scale based on the analytical method is very clear and fast;

[0052] 3. The analysis of the contact behavior of the rough surface of the rubber seal on the microscale based on the numerical method has the advantages of digitization and intellectualization, and can be completed without relying on experiments, which improves the prediction speed of the low temperature sealing performance of the hydrogen fuel cell in engineering practice and shortens the structure design cycle.

[0053] 4. The present application provides a multi-scale prediction method for the sealing performance of the hydrogen fuel cell, which is of great significance for improving the calculation accuracy of the leakage rate of the hydrogen fuel cell under low temperature.

[0054] The present application is described in detail in combination with the accompanying Figure 3 The influence of the temperature-induced shrinkage behavior on the actual compression rate of the rubber seal of the hydrogen fuel cell under low temperature on the macroscopic scale is described as follows:

[0055] Macroscopically, the seal can be considered effective when the contact stress of the sealing interface is greater than the pressure of the sealed medium. In the sealing structure of the hydrogen fuel cell, the soft rubber seal bears the main sealing compression load and undergoes nonlinear large deformation, and the study of the macroscopic contact mechanics behavior of the sealing interface is an important basis for realizing the low-temperature sealing performance modeling of the hydrogen fuel cell. The compression rate of the hydrogen fuel cell rubber seal is defined as the compression deformation degree of the cross section caused by the compression after the seal is installed in the sealing groove:

[0056]

[0057] Wherein H is the thickness of the rubber seal in the free state; B is the depth of the sealing groove. However, in a low-temperature environment, the size of each component of the hydrogen fuel cell will inevitably change, and since the low-temperature shrinkage coefficient of the rubber material is much larger than that of metal and other materials, it is believed that the metal bipolar plate in the hydrogen fuel cell sealing interface does not undergo cold shrinkage and size change, and the actual compression amount of the hydrogen fuel cell rubber seal under low-temperature load is:

[0058] ΔH t初 =H t -B=H×[1-α×(25-t)]-B

[0059] Wherein H t is the thickness of the hydrogen fuel cell rubber seal under the influence of low-temperature load; t is the specific temperature of the low-temperature environment; and α is the temperature-induced shrinkage coefficient of the rubber material of the seal.

[0060] The current design working life of the hydrogen fuel cell has exceeded 5000 hours, and the long-term low-temperature sealing performance of the seal is directly affected by the resilience characteristics of the rubber material. This is because the elastic modulus of the rubber seal rises after being in a low-temperature environment for a long time and has an irreversible characteristic, which results in the thickness of the seal in the free state being unable to fully recover to the initial level even after returning to room temperature. Under the condition that the compression displacement of the hydrogen fuel cell packaging seal does not change, the actual compression amount of the seal at low temperature is necessarily much smaller than the nominal value:

[0061] ΔH t =K C ×(H t -H)

[0062] Wherein k C is the compression cold resistance coefficient of the rubber seal material in the low-temperature environment, which indicates the degree of elasticity reduction of the rubber in the low-temperature environment, and k C =1 when t=25℃. Then the actual low-temperature compression rate of the hydrogen fuel cell seal in the low temperature t is:

[0063]

[0064] Appendix Figure 3In the experimental group, the compression ratio decreased linearly with the decrease of temperature, and the change of the compression ratio was not obvious due to the small cold shrinkage coefficient of the rubber seal material. However, the compression ratio curve considering the decrease of the elasticity of the rubber seal at low temperature showed significant non-linear characteristics and a larger change range, which proved the important influence of the decrease of the elasticity of the rubber material on the actual compression ratio of the hydrogen fuel cell seal at low temperature.

[0065] The experimental results of the rubber seal surface micro-morphology on the sealing interface contact state are shown in FIGS. 1 and 2. Figure 4 The experimental results of the rubber seal surface micro-morphology on the sealing interface contact state are shown in FIGS. 1 and 2. Figure 4 (a) is the experimental group result, which considers the influence of rough morphology on the sealing interface contact behavior, and the result has multi-scale characteristics. Figure 4 (b) does not consider the influence of the rubber seal surface micro-morphology on the interface contact behavior result.

[0066] In the experimental group, the compression ratio decreased linearly with the decrease of temperature, and the change of the compression ratio was not obvious due to the small cold shrinkage coefficient of the rubber seal material. However, the compression ratio curve considering the decrease of the elasticity of the rubber seal at low temperature showed significant non-linear characteristics and a larger change range, which proved the important influence of the decrease of the elasticity of the rubber material on the actual compression ratio of the hydrogen fuel cell seal at low temperature. Figure 4 As can be seen from FIG. 1, when the temperature decreases from 25°C to -40°C, the maximum contact stress of the hydrogen fuel cell sealing interface decreases from 4.61 MPa to 1.18 MPa, with a change rate of 74.40%; the average contact stress decreases from 1.60 MPa to 0.03 MPa, with a change rate of 98.31%. However, the degree of decrease of the interface contact stress is significantly different in different low-temperature environments, for example, in the interval of 0°C to -30°C, the maximum and average values of the contact stress only decrease by 3.71% and 43.34% respectively, which proves the significant influence of ultra-low temperature on the performance of the multi-layer ultra-thin sealing structure of the hydrogen fuel cell.

[0067] In the control group, only the macroscopic matrix part of the rubber seal model is affected by the low-temperature load thermoshrinkage, and the surface micro-morphology remains unchanged at room temperature. Figure 4 In the control group, only the macroscopic matrix part of the rubber seal model is affected by the low-temperature load thermoshrinkage, and the surface micro-morphology remains unchanged at room temperature. Figure 4 In the experimental group, the compression ratio decreased linearly with the decrease of temperature, and the change of the compression ratio was not obvious due to the small cold shrinkage coefficient of the rubber seal material. However, the compression ratio curve considering the decrease of the elasticity of the rubber seal at low temperature showed significant non-linear characteristics and a larger change range, which proved the important influence of the decrease of the elasticity of the rubber material on the actual compression ratio of the hydrogen fuel cell seal at low temperature.

[0068] The complex influence of low-temperature load on the leakage channel parameters of the hydrogen fuel cell sealing interface is shown in FIG. 3, and a multi-scale prediction method for the low-temperature sealing performance of the hydrogen fuel cell is established by combining the macro-scale analytical modeling and the micro-scale numerical research, which is described as follows: Figure 5 The complex influence of low-temperature load on the leakage channel parameters of the hydrogen fuel cell sealing interface is shown in FIG. 3, and a multi-scale prediction method for the low-temperature sealing performance of the hydrogen fuel cell is established by combining the macro-scale analytical modeling and the micro-scale numerical research, which is described as follows:

[0069] In this example, the maximum contact stress decreases significantly with the application of cryogenic loading, indicating that cryogenic loading smoothes the surface microstructure of the rubber seal. This improves the uneven contact distribution within the multi-layer, ultra-thin sealing interface of hydrogen fuel cells, reduces the number of interfacial leakage channels, and improves interfacial sealing performance. However, the multi-scale method actually predicts lower results for low-temperature hydrogen fuel cell sealing. This is because changes in the surface microstructure of the rubber seal at low temperatures not only affect the number of interfacial leakage channels but also determine the center locations of rough protrusions and depressions, thereby affecting the overall height of the interfacial leakage channels.

[0070] Attachment Figure 5 The paper demonstrates the influence of different models on the height of leakage channels at the interface of a multilayer, ultra-thin hydrogen fuel cell seal under low-temperature loading. The multiscale approach predicts leakage channel height at the hydrogen fuel cell seal interface better than traditional models, demonstrating the multifaceted impact of micromorphological changes on the low-temperature sealing performance of the interface.

[0071] Therefore, the multi-scale prediction method for the low-temperature sealing performance of hydrogen fuel cells involved in the present invention can be expressed as:

[0072] σ mul =σ tra +σ(D t )-σ(h t )

[0073] where σ tra is the actual low-temperature compression rate of the rubber seal in the macroscopic scale in Example 1. The second and third terms respectively represent the improvement and inhibition of the interface sealing performance caused by the change of the surface micromorphology of the seal at low temperature. t ), the multi-scale average contact stress will increase with the change of topography, which can be specifically expressed as:

[0074] σ(D t )=η t ·E t ·f(D t )-η·E·f(D)

[0075] Among them, D and D t Refers to the surface microscopic morphology characteristic parameters of rubber seals at room temperature and low temperature, f(D) and f(D t ) are the equations governing the micromorphology of the seal surface, which can be fitted experimentally or numerically. On the other hand, low-temperature loads affect the position of the micromorphology centerline, changing the height of the leakage channel at the hydrogen fuel cell seal interface. Their impact on the low-temperature sealing performance of hydrogen fuel cells can be expressed as:

[0076]

[0077] where h and h t The interface leakage channel height of the multilayer ultra-thin sealing structure of the hydrogen fuel cell under the influence of the micro-morphology characteristics of the sealing surface in the normal temperature and low temperature environments respectively, and thus it can be expressed as:

[0078]

[0079] The multi-scale prediction method for the low temperature sealing performance of the hydrogen fuel cell can be expressed as:

[0080]

[0081] The present application characterizes the temperature-induced shrinkage behavior of the macroscopic matrix of the PEMFC sealing element at low temperature by using the conventional analytical model, and expresses the influence of the micro-morphology of the sealing element on the interface contact characteristics by using the sigma (D t ) and sigma (h t ), and proposes a multi-scale prediction method for the low temperature sealing performance of the hydrogen fuel cell.

[0082] The above detailed the preferred embodiments of the present application. It should be understood that those of ordinary skill in the art can make many modifications and variations without creative work based on the concept of the present application. Therefore, any technical solution obtained by logical analysis, reasoning or limited experiment based on the existing technology according to the concept of the present application shall be within the protection scope defined by the claims.

Claims

1. A multi-scale prediction method for low-temperature sealing performance of hydrogen fuel cells, characterized in that the method The application relates to a method for predicting the low-temperature sealing performance of a hydrogen fuel cell. S1, calculate the initial actual compression amount of the hydrogen fuel cell rubber seal under low temperature load, and obtain the modified compression rate ΔH after optimizing the actual compression amount t ; S2, obtain the actual low temperature compression rate η of the hydrogen fuel cell seal t ; S2, based on the numerical method, analyzing the influence of the surface micro-morphology of a rubber sealing element on the contact characteristics of a sealing interface of a hydrogen fuel cell at low temperature, obtaining an improvement item and an inhibition item of the surface micro-morphology change of the sealing element at low temperature on the sealing performance of the interface; S3, obtaining a hydrogen fuel cell low-temperature sealing performance prediction result based on the improvement item and the inhibition item and an actual low-temperature compression rate; The actual compression amount is: ΔH t初 = H t -B = H x [1 - a x (25 - t)] - B wherein H t is the thickness of the hydrogen fuel cell rubber seal under the influence of low temperature load; t is the specific temperature of the low temperature environment; a is the temperature-induced shrinkage coefficient of the seal rubber material, H is the thickness of the rubber seal in a free state; and B is the depth of the seal groove. Correction compression rate ΔH t is: ΔH t = K C × (H t -B) K C is the compression cold resistance coefficient of the rubber sealing material under low temperature environment; Actual low temperature compression ratio η t is: The hydrogen fuel cell low-temperature sealing performance prediction result is: σ mul = σ tra + σ(D t ) - σ(h t ) wherein σ tra represents the actual low-temperature compression ratio η t , σ(D t ) represents an improvement term of the interface sealing performance due to the change in the microtopography of the sealing surface at low temperature, and σ(h t ) represents an inhibition term of the interface sealing performance due to the change in the microtopography of the sealing surface at low temperature. The improvement item of the surface micro-morphology change of the sealing element at low temperature on the sealing performance of the interface is: σ(D t ) = η t · E t · f(D t ) - η · E · f(D) wherein D and D t respectively refer to the micro-morphology characteristic parameters of the rubber seal surface under normal temperature and low temperature environment, f(D) and f(D t ) are respectively the micro-morphology change rule equations of the seal surface, η represents the compression deformation degree caused by the extrusion section, E and E t respectively represent the mechanical characteristic parameters of the seal rubber material under normal temperature and low temperature. The inhibition item of the surface micro-morphology change of the sealing element at low temperature on the sealing performance of the interface is: where h and h t Interface leakage channel height of multilayer ultra-thin seal structure of hydrogen fuel cell under the influence of surface micro-morphology characteristics of seal in normal and low temperature environment, respectively.

2. The method of claim 1, wherein, The surface micro-morphology change rule equation of the sealing element is fitted by an experimental method.

3. The method of claim 1, wherein, The surface micro-morphology change rule equation of the sealing element is fitted by a numerical method.

4. The method of claim 1, wherein, The compression rate represents the compression deformation degree of the sealing element after being installed into a sealing groove due to the extrusion section.

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